Automatic control for arc lamps



March 29 1927. 1,622,505

C. M. FOX

AUTOMATIQCONTROL FOR ARC LAMPS Filed Aug. 6, 1925 anomm i atented Mar.29, 1927.

UNITED STATESPATE'NT orrlcui CECIL M. FOX, 01? TOLEDO, OHIO.

AUTOMATIC CONTROL FOR ARC LAMPS.

Application filed August 6, 1925. Serial No. 48,575.

viding an electrically operated device for controlling the speed of thecarbon in an arc lamp wherein the variation in potential across the arcis utilized for controlling the operation of the automatic feed deviceso that the carbons of the lamp are maintained at the proper distanceapart for producing the most eficient are light.

Another object of the invention resides in providing an arclampstructure with an automatic feed device wherein a reversible .motoris provided with independent fields for controlling the rotation of thearmature adapted to be energized alternately for pro ducing a forward orreverse feed of the carbon to vary the gap automatically in accordancewith the variance in potential acrosssaid gap, means being provided formanually controlling the operation of the device for adjusting theoperation thereof in order that the proper gap may be maintained betweenthe carbons for producing a most eiiicient are light.

The inyention comprehends other objects and improvements in the detailsof construction and arrangement of the parts which are more particularlypointed out in the following detailed description and in the claims,directed to apreferred form of the invention, it being understoodhowever, that various changes inthe details of construction may be madefor carrying out the principle of the invention without departing fromthe spirit or scope thereof as herein set forth.

Tn the drawing forming partof this application,

The view is a diagrammatic illustration of the carbon of an arc lamp andthe mechanism forming the subject matter of the pres ent invention,shown inits operation relation therewith. I

1 indicates a bracket supporting the positive carbon 2 while thenegative carbon 3. is

mounted in the bracket 4, both ofwhich brackets are slidably mounted inorder to.

permit an axial movement of the carbon so that the gap may be adjustedin order to maintain the proper are for producing the most efiicientlight. "A feed screw 5 pro-.

vidcd with reverse threads on the opposite end portion thereofthreadedly engages the brackets 1 and 4 so that in the rotation of 9.The armature of the motor has the usual commutator 15 with which thebrushes 16 and 17, engage in the usual manner.

The posltive and negative conductors from a suitable source of power areillustrated at 18 and 19 respectively, the conductor 18 being connectedwith the carbon supporting bracket 1 for interposing the positive carbon2 in circuit with the source of energy, while the negative conductorfrom the source of power extends to the resistance 20 which is of afixed and predetermined character from which the'wire 21 extends to thebracket 4 of the negative carbon. A wire connection 22 extends from thepositive conductor 18 to one terminal of the field 12 while the oppositeterminal of the field 12 is connected with the wire 23 to one terminalof the field 13. The top of the terminal or field 13 is connected by thewire 24 to the variable resistance 25 which has the opposite terminalthereof connected to the negative conductor 19. A wire connection 26 isconnected to character, the potential varies across thecarbon inaccordance with the length of the arc, advantage being taken of' thisvariation of potential across the carbon for the purpose of controllingthe motor in order that the proper feed and arc may be maintainedautomatically. When the resistance across the positive and negativecarbons 2 and 3 respectively is high due to a substantially large gapbetween the carbon, producing a'snbstantiall long are or no are at all,current will ow from the positive conductor l8 through the wire 22 tothe field 12, then through the wire 23 to the wire '26 and through thebrushes 17 the armature 11, and to the brush 16 trom which current flowsto the negative side of the line through the wire 27 and 21 and throughresistance 20. This flow of current will produce an operation of-thearmature to rotate the shaft 14: and the worm 9 and thereby rotate thefeed screw 5 in order to feed the carbons toward each other for thepurpose of striking the are. As the carbons engage and strike the arcthe resistance across the carbons will be substantially low as a resultof which the current will flow from the positive side of the lampthrough the carbons 2 and 3 and through the wire 27 to the brush 16'.From the brush 16 it will fiow through the' commutator 15 and armature11 to the brush 17 and wire 23. The current will then flow into-thefield 13 and through wire 2e and variable resistance 25 to the negativeside of the line in view of the fact that the resistance through thiscircuit is less than the resistance through the wire'21 and resistance20. This rotation of the armature from that caused by the field12 andthe energization of the circuit above mentioned which will produce amovement of the carbons away from each other after the arc is struck inorder to lengthen the same which will increase the brilliancy of the arcand the light produced thereby. This operation will take place un- '12atwhich time the same til the carbons are separated to increase theresistance across the are between the electrodes 2 and 3 to a pointwhere the current which fiows through the field 12 will build up to rentflow in the field 13, which will efiect a balance in the circuit throughthe fields 12 and 13. as above mentioned and will hold the armaturestationary.

After thearc is struck and the armature rotates in a reverse direction,it will gradually slow down as the potential increases across the arcuntil it is equalized in the arc circuit and the circuit through thefield will be held stationary, and upon any variance in the potentialdue to the burning away of the carbon which will increase the are andincrease the potential, the armature will be operated by the field 20suificient-ly to move the carbonstogether in order to maintain a uniformarc; The distance at which this are is maintained is controlled by theposition of the variable resistance 25 whichcontrols the balance in thecircuit and thereby controls the position at which the mohas: beenprovided for will produce a reverse an extent to equalize the curautomatically striking the are between the carbons of an arc lamp andthereafter maintaining such a gap between the carbons as will producethe most efficient light generation. This automatic control is producedas above described in accordance with the variation of potential acrossthe arc and through the two circuits, each including one of theindependent fields of the motor which controls the operation of thereversible motor to produce in a most simple manner the proper automaticcontrol of-vthe arc.

Having thus described my invention, what I claim as new is I 1. In anarc lamp, electrodes, a motor to cause adjustment of said electrodes,said motor comprising independent field windin'gs and an armature, andmeansto supply current to said motor when the electrodes need adjustmentincluding means to cause current to pass through the armature in oneirection and to energize afield winding to have a dominating effectthereon when the are resistance is too high and to cause current to passthrough the armature in the other direction and to energize anotherthereon when the arc-resistance is too low.

2. In an arc lamp, electrodes, a motor to i cause adjustment of saidelectrodes, said motor comprising windings and an armature, and means tosupply current to said motor when the electrodes need adjustmentincluding means to cause current to pass through the armature in onedirection and to energize a field winding to have a dominating ctlectthereon when the arc resistance is too high andto cause current to passthrough the armature in the other direction and to energize the otherfield winding to have a dominating eti'ect thereon when the arcresistance is too low.

3. In an arc lamp, electrodes, a motor to cause adjustment of saidelectrodes, said motor comprising independent field windings and anarmature, and means to supply current to said motor when the electrodesneed adjustment including means to cause current the armature 1n onedito pass through rection and to energize a field winding to have adommating effect thereon when the two independent field,

are resistance is too high and to cause cnrrent to pass through thearmature in the other direction and to energize another. field windingto'have a dominating eil'ect thereon when the are resistance is too low,the cur-- rent passing through the one field winding passingtherethrough in the same direction whether the arc resistance be high orlow, and the current passing through the other field winding passingtherethrough in the same direction whether the arc resistance be high orlow. I

4. In an arc lamp, electrodes, a motor to cause adjustment of saidelectrodes, said windings being stone bridge,'a source motor comprisingtwo independent fieldwindings and an armature, and means to supplycurrent to said motor when the electrodes need adjustment includingmeans tocause current to pass through the armature in one direction andto energize a field winding to have a dominating efi'ect thereon whenthe arc resistance is too high and to cause current to pass through thearmature in the other direction and to energize the other field windingto have a dominating effect thereon when the arc resistance is too low,the current passing through the one field winding passing therethroughin the same direction whether the arc resistance be high or low, and thecurrent other field winding the same direction be high or low.

5. In an arc lamp, a \Vheatstone bridge, electrodes adapted to form anarc in one leg of said bridge, a motor con'iprising an armature and twofield windings, one of said field windings being in another leg of said\Vheatstone bridge,

passing through the passing therethrough in whether the arc resistancestone bridge, the armature being connected across the meeting point oftwo legs of said WVheatstone bridge and the meeting point of the othertwo legs of said \Vheatstone bridge, and a source of power connectedacross the other two meeting points of said bridge legs, wherebythe arcwill be maintained at a constant value. a

6. In an arc lamp, a lVheatstone bridge, electrodes adapted to form anarc in one leg of said bridge, a motor comprising an-armature and twofield windings, one of said field windings being in another leg I ofsaid \Vheatstone bridge, the other of said field in another leg of saidlVheatstone bridge, the armature being connected across the meetingpoint of two legs of said \Vheatstone bridge and the meeting point ofthe other two legs of said Vheatof power connected across i he other twomeeting points of said bridge legs, whereby the arc will be maintainedat a constant value. and an adjustable resistance in a leg with a fieldwinding whereby the constant value of the arc may be predetermined andvaried.

7.'In an arc lamp, a VVheatstone bridge, electrodes adapted to form anarc in one leg of said bridge, a motor comprising an armatureand twofield windings, one of said field windings being in a leg of saidVVheatstone' bridge adjacent to said first mentioned leg.

a connection for one side of a source of power at the meeting point ofsaid legs, the

' connection for one side of a source the other of said field windingsbeing in another leg of said Wheatother field winding being in a leg ofsaid Wheatstone bridge adjacent to said second mentioned leg, aresistance in the fourth leg of said \Vhcatstone bridge, said fourth legbeing adjacent said first mentioned and third mentioned legs, aconnection at the meeting point of said third and fourth mentioned legsfor the other side of the source of power, said armature being connectedbetween the meeting point of said first and fourth mentioned legs andthe meeting point of said second and third mentioned legs.

8. In an arc lamp, a Wheatstone bridge, electrodes adapted to form ofsaid bridge, a motor comprising an armature and two field windings, oneof said field windings being in a leg of said lVheatstone briogeadjacent to said first mentioned leg, at of power at the meeting pointof said legs, the other field winding being in a leg of said \Vhcatstonebridge adjacent to said second mentioned leg, a resistance in the fourthleg of said lVheatstone bridge, said fourth leg being adjacent saidfirst mentioned and third mentioned legs, a connection at the meetingpoint of said third and fourth mentioned legs for the other side of thesource of power, said armature being connected between the meeting pointof said first and fourth mentioned legs and the meeting point of saidsecond and third mentioned legs, and an adjustable resistance in a legwith one of said field windings.

9. In an arc lamp, a \Vheatstone bridge, electrodes adapted to form anarc in one leg of said bridge, a motor comprising an armature and twofield windings, one of said field windings being in a leg of saidWheatstone bridge adjacent to said first mentioned leg, :1 connectionfor one side of a source of power at the meeting point of said legs, theother field winding being in a leg of said Wheatstone bridge adjacent tosaid second mentioned leg, :1 of said lVheatstone bridge, said fourthleg being adjacent said first mentioned and third mentioned legs, aconnection at the meeting point of said third and fourth mentioned legsfor the other side of the'source of power, said armature being connectedbetween the meeting point of said first and fourth mentioned legs andthe meeting point of said second and third mentioned legs, and anadjustable resistance in the third mentioned leg including said secondmentioned field winding.

In testimony whereof I afiix my signature.

CECIL M. FOX.

an arc in one leg resistance in the fourth leg

